Electronic device with electrode and its manufacture

ABSTRACT

A method of manufacturing an electronic device includes the steps of: (a) preparing a (001) oriented ReO 3  layer; and (b) forming a (001) oriented oxide ferroelectric layer having a perovskite structure on the ReO 3  layer. Preferably, the step (a) includes the steps of: (a-1) preparing a (001) oriented MgO layer; and (a-2) forming a (001) oriented ReO 3  layer on the MgO layer. An electronic device capable of obtaining a ferroelectric layer of a large polarization and a method of manufacturing the same are provided.

CROSS REFERENCE TO RELATED APPLICATION

This is a divisional application which claims the benefit of pendingU.S. patent application Ser. No. 10/076,349 now U.S. Pat. No. 6,744,085,filed Feb. 19, 2002. The disclosure of the prior application is herebyincorporated herein in its entirety by reference.

This invention is based on and claims priority of Japanese patentapplication 2001-329688, filed on Oct. 26, 2001, the whole contents ofwhich are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electronic device having aferroelectric layer and a method of manufacturing the same, moreparticularly to an electronic device having a ferroelectric layeroriented crystallographically and a method of manufacturing the same.

2. Description of the Related Art

A semiconductor memory, in which one memory cell is constituted of onetransistor and one capacitor, has been widely known. A capacitor of adynamic random access memory (DRAM) has a capacitor dielectric layerformed of a paraelectric material. Electric charges stored in thecapacitor gradually decrease therefrom due to their leak even when thetransistor is turned off. Accordingly, when a voltage applied to thememory cell is removed, information stored therein decreases anddisappears before long.

A memory capable of retaining information stored therein even afterpower is cut off is called a non-volatile memory. As a kind of thenon-volatile memory, a one-transistor/one-capacitor type memory, acapacitor dielectric layer of which is formed of a ferroelectricmaterial, has been known, which is called a ferroelectric random accessmemory (FeRAM).

The FeRAM utilizes residual polarization of the ferroelectric materialas information stored therein. The FeRAM controls a polarity of avoltage applied between a pair of electrodes of the ferroelectriccapacitor, thus controlling the direction of the residual polarization.Assuming that one polarization direction be “1” and the other be “0”,binary information can be stored. Since the residual polarizationremains in the ferroelectric capacitor even after the applied voltage isremoved therefrom, the non-volatile memory can be realized. In thenon-volatile memory, information can be rewritten by a sufficient numberof times, that is, 10¹⁰ to 10¹² times. The non-volatile memory also hasa rewriting speed of an order of several ten nanoseconds and offers ahigh-speed operability.

As ferroelectric materials, lead-based oxide ferroelectric materialshaving a perovskite structure and bismuth-based oxide ferroelectricmaterials having a bismuth-layered structure have been known. Typicalexamples of the lead-based ferroelectric materials arePbZr_(x)Ti_(1-x)O₃ (PZT), Pb_(y)La_(1-y)Zr_(x)Ti_(1-x)O₃ (PLZT) and thelike. A typical example of the bismuth-based oxide ferroelectricmaterials is SrBi₂Ta₂O₉ (BST).

The ferroelectric capacitor offers a higher charge retention capabilityas the polarization of the ferroelectric material is greater, and canretain the electric potential with less capacitance. Specifically, theFeRAM can be fabricated with high integration. Furthermore, as thepolarization of the ferroelectric material is greater, the polarizationdirections can be differentiated more clearly even at a low reading-outvoltage, thus enabling the ferroelectric memory to be driven at a lowvoltage.

It is effective to arrange orientations of ferroelectric crystalsuniformly in order to increase a polarization amount of theferroelectric material. For example, on pages 382 to 388 of “Journal ofApplied Physics” 1991, vol. 70, No. 1, disclosed is a technology ofobtaining a (111)-oriented ferroelectric thin film, in which metal thinfilms formed of metals such as platinum (Pt) and iridium (Ir) aredeposited at 500° C. to obtain a (111)-oriented metal thin film, and aferroelectric thin film such as PZT is deposited on this metal thin filmat a room temperature, followed by heating of the depositedferroelectric thin film to a range from 650° C. to 700° C. However, themaximum temperature permitted for a manufacturing process of the FeRAMis usually 620° C.

The ferroelectric material such as PZT having a tetragonal simpleperovskite structure has a polarization axis along the c axis <001>.Accordingly, the polarization amount becomes maximum when theferroelectric layer is approximately oriented along a (001) plane(hereinafter, referred to as (001)-oriented). When the ferroelectriclayer is (111)-oriented, a component of the polarization produced in<001> direction is only about 1/1.73 in <111> direction that is athickness direction of the ferroelectric layer. Although thepolarization can be increased by aligning orientation, it is impossibleto increase the polarization to the maximum.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an electronic devicecapable of obtaining a ferroelectric layer having a large polarizationamount and a method of manufacturing the same.

Another object of the present invention is to provide an electronicdevice provided with a (001)-oriented ferroelectric layer and a methodof manufacturing the same.

Still another object of the present invention is to provide anelectronic device provided with a ferroelectric capacitor having a ReO₃layer as at least one of electrodes and a method of manufacturing thesame.

According to one aspect of the present invention, there is provided anelectronic device including: a ReO₃ layer having a (001) orientation;and an oxide ferroelectric layer having a perovskite structure, theoxide ferroelectric layer being formed on the ReO₃ layer and having a(001) orientation.

According to another aspect of the present invention, there is provideda method of manufacturing an electronic device, including the steps of:preparing a ReO₃ layer having a (001) orientation; and forming an oxideferroelectric layer having a perovskite structure on the ReO₃ layer, theoxide ferroelectric layer having a (001) orientation.

A (001)-oriented MgO layer is preferably used as an underlying layer ofthe ReO₃ layer.

Lattice matching can be made for the (001)-oriented ReO₃ layer and the(001)-oriented oxide ferroelectric layer having a perovskite structure;accordingly, the (001)-oriented oxide ferroelectric layer having aperovskite structure can be formed on the (001)-oriented ReO₃ layer.

The MgO layer can be easily (001)-oriented. The lattice matching can bemade for the (001)-oriented MgO layer and the (001)-oriented ReO₃ layer.Hence, the (001)-oriented ReO₃ layer and the (001)-oriented oxideferroelectric layer having a perovskite structure can be formed on the(001)-oriented MgO layer sequentially.

The term “ReO₃” used herein includes ReO₃ to which metal other than Reis added, for example, for controlling a lattice constant thereof.

In such a manner as described above, it is possible to form aferroelectric capacitor capable of realizing greater polarization.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic cross-sectional view of an electronic device;FIG. 1B is a schematic block diagram showing a constitution of ametalorganic chemical vapor deposition (MOCVD) apparatus; FIG. 1C is aschematic cross-sectional view showing an upper electrode of theelectronic device when a stacked structure is adopted therefor; and FIG.1D is a schematic cross-sectional view of the electronic device when asingle crystal MgO layer is used therefor, all of which are made forillustrating embodiments of the present invention.

FIGS. 2A and 2B are structural views showing chemical formulae ofMg(DPM)₂ and i-PrO.

FIGS. 3A and 3B are cross-sectional views of constitutional examples ofan electronic device having a ferroelectric capacitor according toembodiments of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, description will be made on embodiments of the presentinvention with reference to the drawings.

FIG. 1A shows a structure of a ferroelectric capacitor according to afundamental embodiment of the present invention. A silicon oxide layer11 is formed on a Si substrate 10. The silicon oxide layer 11 can beformed by thermal oxidation of silicon, chemical vapor deposition (CVD)or the like. The silicon oxide layer 11 may be formed by other methods.The silicon oxide layer 11 has an amorphous phase. A (001)-oriented MgOlayer 12 is formed on the silicon oxide layer 11, a (001)-oriented ReO₃layer 13 is formed on the MgO layer 12, and a (001)-oriented PZT layer14 is formed on the ReO₃ layer 13.

The (001)-oriented MgO layer 12, the (001)-oriented ReO₃ layer 13 on theMgO layer 12 and the (001)-oriented PZT layer 14 on the ReO₃ layer 13,the PZT layer 14 being a ferroelectric layer having a perovskitestructure, can be deposited by metalorganic chemical vapor deposition(MOCVD) using a metalorganic (MO) material.

FIG. 1B schematically shows a structure of an apparatus for depositing afilm by MOCVD. A liquid container 21-1 contains a metalorganic materialsolution used for deposition. Pressurized He gas is fed to the liquidcontainer 21-1 from a pipe opened to a space on the solution, thusenabling the solution to be supplied to another pipe 22-1 deeplyintruded into the solution. A flow rate of the supplied solution iscontrolled by a mass flow controller (MFC) 24-1, and the solution issupplied to a vaporizer 27-1 through a pipe 25-1.

A carrier gas pipe 26 is connected to the vaporizer 27-1. The liquid rawmaterial solution supplied to the vaporizer 27-1 together with carriergas N₂ is vaporized by the vaporizer 27-1 and supplied to a pipe 28-1.

A liquid container 21-2, a pipe 22-2, a mass flow controller 24-2, apipe 25-2, a vaporizer 27-2 and a pipe 28-2 have similar structures asthose of the liquid container 21-1, the pipe 22-1, the mass flowcontroller 24-1, the pipe 25-1, the vaporizer 27-1 and the pipe 28-1,which are described above, respectively. Furthermore, any number ofsimilar raw material supply systems may be provided.

The vaporizer 27-1 may be connected with other liquid raw materialsupply systems having similar structures as those of the liquidcontainer 21-1, the pipe 22-1, the mass flow controller 24-1 and thepipe 25-1. Other vaporizers can also be provided with any number of theliquid raw material supply systems.

A reaction chamber 30 has raw material pipes such as a gas pipe 29 andthe liquid raw material pipes 28-1, 28-2 . . . , and can supply rawmaterial gas from a showerhead 32. A susceptor 34 capable of controllinga temperature thereof is disposed at a lower portion of the reactionchamber 30, and a substrate 35 composed of, for example, a siliconsubstrate provided with a silicon oxide layer is disposed on thesusceptor 34.

In the above description, an example is shown, in which the raw materialsupply systems are provided in plural; however, a single system may beemployed. Moreover, an example of a single reaction chamber is shown;however, a plurality of the reaction chambers may be provided.

With regard to a metalorganic material contained in the liquidcontainers, for example, as a Mg raw material, a solution obtained bydissolving Mg(DPM)₂ (where DPM is dipivaloilmethanate) in thetetrahydrofuran (THF) can be used.

FIG. 2A is a chemical formula showing a chemical structure of Mg(DPM)₂.Dipivaloilmethanate (DPM) is bonded at each side of a Mg atom. DPM ismonovalent, and n pieces of DPMs can be bonded to an n-valent atom.

As a Re material, a solution obtained by dissolving Re(DPM)₂ in THF canbe used. A chemical formula of Re(DPM)₂ is equivalent to that obtainedby replacing Mg with Re in the chemical formula shown in FIG. 2A.

As a Pb material, a solution obtained by dissolving Pb(DPM)₂ in THF canbe used. A structure of Pb(DPM)₂ is equivalent to that obtained byreplacing Mg with Pb in the structure shown in FIG. 2A.

As a Zr material, a solution obtained by dissolving Zr(DPM)₄ in THF canbe used. Zr(DPM)₄ has a structure where four DPMs are bonded around oneZr atom.

As a Ti material, a solution obtained by dissolving Ti (i-PrO)₂(DPM)₂(where i-PrO is an iso-proxy group) in THF can be used. A structure ofTi (i-PrO)₂(DPM)₂ is equivalent to that obtained by replacing Mg with Tiin the structure shown in FIG. 2A and by bonding two iso-proxy groupsshown in FIG. 2B to Ti. Note that the metalorganic (MO) material is notlimited to these examples.

In order to deposit the MgO layer 12 shown in FIG. 1A, pressurizedhelium (He) gas is fed to the liquid containers 21 containing thesolution obtained by dissolving Mg(DPM)₂ in THF, and the solution ismade to pass through the vaporizers 27 heated at 260° C., vaporized, andloaded on the carrier gas N₂.

The Mg raw material, for which N₂ is used as carrier gas, is fed throughthe pipes 28 to the showerhead 32, and supplied to the silicon oxidefilm on the substrate 35 together with O₂ gas supplied from the pipe 29.The silicon oxide film is heated to 560° C., decomposes the suppliedmetalorganic gas, and combines the decomposed gas with oxygen, thusdepositing a (001)-oriented MgO layer. A thickness of the (001)-orientedMgO layer is set, for example, in a range from 50 to 100 nm.

Deposition temperature is not limited to 560° C. Preferably, depositionis carried out with substrate temperature of 620° C. or lower.Accordingly, a step of the deposition can be harmonized with othermanufacturing steps for the FeRAM device.

Next, description will be made for the case of depositing the ReO₃ layer13 on the (001)-oriented MgO layer 12. In order to deposit the ReO₃layer 13, the liquid raw material obtained by dissolving Re(DPM)₂ inTHF, which is contained in the liquid containers 21, is used, and themetalorganic material loaded on the carrier gas is fed to the showerhead32 in the same manner as the above-described process. To the showerhead32, O₂ gas, mixed gas of O₂ gas and N₂ gas or the like is simultaneouslysupplied.

The substrate 35 having the (001)-oriented MgO layer 12 formed thereonis kept at a constant temperature of 560° C. by means of the susceptor34. The raw material gas is supplied onto the (001)-oriented MgO layer12 kept at 560° C., whereby the (001)-oriented ReO₃ layer 13 isdeposited. A thickness of the (001)-oriented ReO₃ layer 13 is set, forexample, in a range from 20 to 50 nm.

After the (001)-oriented ReO₃ layer 13 is deposited, the PZT layer 14 isdeposited thereon. For the PZT, as a Pb raw material, the solutionobtained by dissolving Pb(DPM)₂ in THF is used; as a Zr raw material,the solution obtained by dissolving Zr(DPM)₄ in THF is used; and as a Tiraw material, the solution obtained by dissolving Ti (i-PrO)₂(DPM)₂ inTHF is used. Pressurized helium gas is fed to three liquid containerscontaining these liquid raw materials, and the liquid raw materials arevaporized by one or three vaporizers and supplied to the showerhead 32.

The substrate temperature is kept at 560° C., and Pb(DPM)₂ gas, Zr(DPM)₄gas, Ti(i-PrO)₂(DPM)₂ gas and oxygen are simultaneously blown onto thesubstrate, thus the Pb(Zr, Ti)O₃ (PZT) layer 14 is deposited on the(001)-oriented ReO₃ layer 13. The deposited PZT layer 14 has also (001)orientation. A thickness of the (001)-oriented PZT layer 14 is set, forexample, in a range from 80 to 150 nm.

As described above, an MgO layer is deposited on an amorphous siliconoxide layer 11 by MOCVD, to obtain a (001)-oriented MgO layer 12. On the(001)-oriented MgO layer 12, there can be deposited a ReO₃ layer 13,which is (001)-oriented in accordance with the orientation of theunderlying layer, that is, the MgO layer 12. Furthermore, on the(001)-oriented ReO₃ layer 13, there can be deposited the PZT layer 14,which is (001)-oriented in accordance with the orientation of theunderlying layers, that is, the MgO layer 12 and the ReO₃ layer 13.

An upper electrode 15 is formed on the PZT layer 14. The upper electrode15 is not required to be (001)-oriented and can be formed of anelectrode material publicly known hitherto. For example, an IrO₂ layeris deposited by MOCVD. In this case, as an Ir raw material, a solutionobtained by dissolving Ir(DPM)₃ in THF is used. Process for vaporizingthe material is similar as that described above. The substratetemperature is kept at 560° C., and Ir(DPM)₃ gas and oxygen aresimultaneously blown thereonto, thus enabling the upper electrode 15made of IrO₂, which is also referred to as an IrO₂ layer, to bedeposited on the PZT layer 14. A thickness of the IrO₂ layer 15 is set,for example, in a range from 100 to 150 nm.

Description has been made for the case of forming the upper electrode 15of an IrO₂ layer; however, various materials can be used for the upperelectrode irrespective of the orientation of the ferroelectric layer.

As shown in FIG. 1C, for the upper electrode, a stacked layer 15obtained by stacking an IrO₂ layer 15-1 and a SrRuO₃ layer 15-2 may beused. Deposition methods other than MOCVD may also be used.

For example, the IrO₂ layer 15-1 can be deposited by sputtering using anIrO₂ target. In this case, the substrate is kept at a room temperature,and the target is sputtered by use of work gas Ar at a vacuum degree of3×10⁻⁴ Torr, thus the IrO₂ layer 15-1 is deposited. A thickness of theIrO₂ layer 15-1 is set, for example, in a range from 100 to 150 nm.

The SrRuO₃ layer 15-2 to be deposited on the IrO₂ layer 15-1 can also bedeposited by sputtering. SrRuO₃ is used as a target, the substrate iskept at a room temperature, the vacuum degree is set at 3×10⁻⁴ Torr, andAr is used as work gas. Under the above-described conditions, the targetis sputtered, and thus the SrRuO₃ layer 15-2 is deposited. A thicknessof the SrRuO₃ layer 15-2 is set, for example, in a range from 10 to 30nm.

Description has been made above for the case of using PZT as aferroelectric material; however, other oxide ferroelectric materialshaving a perovskite structure can be employed. For example,Pb_(y)La_(1-y)Zr_(x)Ti_(1-x)O₃ (PLZT),Pb_(1-a-b-c)La_(a)Sr_(b)Ca_(c)Zr_(1-x)Ti_(x)O₃ (PLSCZT) and the like canbe used.

Moreover, description has been made for the case of using only O₂ gas asa kind of gas. However, mixed gas of O₂ and other gas, for example,O₂/N₂, O₂/Ar, O₂/He and O₂/N₂O, can also be used.

ReO₃ added with a small amount of other metal shows an electricalresistivity of an order of 10⁻⁶ Ω·m at 300° K. A metal layer used as anelectrode can be utilized effectively as long as an electricalresistivity thereof is 10⁻⁵ Ω·m or less. Accordingly, ReO₃ added withthe other metal (metal impurities) can be utilized effectively as suchan electrode of the ferroelectric capacitor.

Note that the MgO layer is deposited on the amorphous silicon oxidelayer 11, thus forming the (001)-oriented MgO layer 12; however, it willbe obvious that a (001) plane of single crystal MgO can be used in placeof the deposited MgO layer.

FIG. 1D shows the case where a ReO₃ layer 13 and a ferroelectric layer14 having a perovskite structure are epitaxially grown in this order ona single crystal MgO layer 12 having a (001) plane, and then an upperelectrode 15 is formed on the ferroelectric layer 14.

Furthermore, it will be possible to deposit the (001)-oriented MgO layer12, ReO₃ layer 13 and ferroelectric layer 14 by, in place of CVD usingthe metalorganic (MO) raw materials, CVD using other raw materials.Similarly, it will be possible to deposit the above (001)-orientedlayers by sputtering.

The ferroelectric layer 14 is (001)-oriented, thus enabling thepolarization caused by application of the voltage to be aligned to adirection perpendicular to the electrode surface. Therefore, it is madepossible to utilize the polarization of the ferroelectric layer mosteffectively.

FIGS. 3A and 3B show constitutional examples of electronic devices, eachusing the ferroelectric capacitor as described above.

FIG. 3A shows an example where electrodes are taken out of upper andlower surfaces of a ferroelectric capacitor. An element isolation region40 is formed on a surface of a Si substrate 10 by shallow trenchisolation (STI). Two MOS transistors are formed in an active regiondefined by the element isolation region 40. The two MOS transistors haveone source/drain region 46 as a common region and other source/drainregions 45 on both sides thereof, which are connected with theferroelectric capacitors, respectively.

On a channel region between the source/drain regions, is disposed aninsulated gate electrode formed of a gate insulating film 41, apolycrystalline gate electrode 42 and a silicide gate electrode 43. Aside spacer 44 is formed on a sidewall of the insulated gate electrode.An amorphous insulating layer 11 made of silicon oxide or the like isformed over surfaces where the semiconductor devices are formed.Furthermore, a (001)-oriented MgO layer 12 is formed on a surface of theamorphous insulating layer 11.

In order to form an extraction electrode for each of the both-sidesource/drain regions 45, a contact hole is formed through the MgO layer12 and the amorphous insulating layer 11. An extraction plug composedof, for example, barrier metal 48 and a tungsten (W) plug 49 is formedin the contact hole. Then, unnecessary electrode layers on the MgO layer12 are removed by, for example, chemical mechanical polishing (CMP).Subsequently, on the MgO layer 12, is formed a ferroelectric capacitorcomposed of the lower ReO₃ layer 13, the ferroelectric layer 14 having aperovskite structure 14 and the upper electrode 15.

The MgO layer 12 is (001)-oriented, thus making it possible to form the(001)-oriented lower ReO₃ layer 13 and the (001)-oriented ferroelectriclayer 14 having a perovskite structure.

After forming the ferroelectric capacitor, an insulating layer 50 madeof silicon oxide or the like is deposited to cover a surface thereof.Moreover, a contact hole is formed through the insulating layer 50, andthen a barrier metal layer 51 and a metal conductive layer 52 made of Wor the like are buried in the contact hole, thus the extractionelectrode is formed. After forming the extraction electrode, unnecessaryelectrode layers on the insulating layer 50 are removed, and upperwirings 54 and 55 are formed. Surfaces of the upper wirings 54 and 55are covered with an insulating layer 60.

FIG. 3B shows a constitution, in which two electrodes are taken out ofthe upper surface of the ferroelectric capacitor. An element isolationregion 40 of silicon oxide formed by local oxidation of silicon (LOCOS)is formed on the surface of the Si substrate 10. One MOS transistor isformed in an active region defined by the element isolation region 40.

On a channel region, is disposed an insulated gate electrode formed of agate insulating film 41, a polycrystalline gate electrode 42 and apolycrystalline silicide gate electrode 43. A side spacer 44 is formedon a sidewall of the insulated gate electrode. Source/drain regions 45and 46 are formed on both sides of the gate electrode by ionimplantation and the like.

An amorphous insulating layer 48 made of silicon oxide or the like isformed to cover the MOS transistor. Plugs 49 for deriving thesource/drain regions 45 and 46 are formed. A silicon nitride layer 59,for example, having an amorphous phase is formed on a surface of theamorphous insulating layer 48 through which the plugs 49 are formed,thus an oxygen shielding layer is formed.

On the amorphous silicon nitride layer 59, a (001)-oriented MgO layer 12is formed. It is conceivable that the (001)-oriented MgO layer 12 can bedeposited as long as its underlying layer is amorphous. On the(001)-oriented MgO layer 12, is formed a ferroelectric capacitorcomposed of a (001)-oriented ReO₃ layer 13, a (001)-orientedferroelectric layer 14 having a perovskite structure and an upperelectrode 15. The lower ReO₃ electrode 13 is extracted along a directionperpendicular to the drawing sheet. An insulating layer 18 made ofsilicon oxide or the like is formed to cover the ferroelectriccapacitor.

Desired portions of the insulating layer 18, MgO layer 12 and siliconnitride layer 59 are removed by etching, to form contact holes. Then, alocal wiring 19 connects the plug 49 exposed in the contact hole withthe upper electrode 15. An insulating layer 50 is further formed tocover the local wiring 19. Through the insulating layer 50, an openingfor exposing the plug 49 on the other source/drain region 46 is formed.The other wiring 55 is formed, filling the opening.

The above-described constitutions around the ferroelectric capacitor andaround the transistor, which are shown in FIGS. 3A and 3B, respectively,are examples, and have no limitative meaning. Various alternations andexchanges may be employed. Multi-layered wiring structure can be formedby other publicly known techniques. As described above, the electronicdevice with the ferroelectric capacitor, for example, a semiconductorintegrated circuit device can be manufactured.

Although the present invention has been described along the embodiments,the present invention is not limited thereto. It will be obvious tothose skilled in the art that various modifications, improvements andcombinations can be made.

1. A method of manufacturing an electronic device, comprising the stepsof: (a-1) forming a MgO layer having a (001) orientation, on anamorphous layer, (a-2) forming a ReO₃ layer having a (001) orientation,on said MgO layer; and (b) forming an oxide ferroelectric layer having aperovskite structure and a (001) orientation, on said ReO₃ layer.
 2. Themethod of manufacturing an electronic device according to claim 1,wherein at least one of said steps (a-1), (a-2) and (b) is done bymetalorganic chemical vapor deposition (MOCVD).
 3. The method ofmanufacturing an electronic device according to claim 2, wherein all ofsaid steps (a-1), (a-2) and (b) are done by MOCVD.
 4. The method ofmanufacturing an electronic device according to claim 2, wherein saidMOCVD is executed at a substrate temperature of 620° C. or lower.
 5. Themethod of manufacturing an electronic device according to claim 2,wherein said MOCVD uses, as organometal raw material, adipivaloilmethanate (DPM) compound of metal or an iso-proxy (i-PrO)compound of metal.
 6. The method of manufacturing an electronic deviceaccording to claim 1, wherein at least one of said steps (a-1), (a-2)and (b) is done by sputtering.
 7. The method of manufacturing anelectronic device according to claim 1, further comprising the step of:(c) forming at least one upper electrode layer on said oxideferroelectric layer.